Purchasing a certificate from CA?

Hi I want to create an SSL certificate with CA to use with paypal payment in userman. What is server platform and how do I obtain CSR info? Can my ISP provide the correct CSR for my static IP? I am a bit confused about being asked for server platform info. Which server is it. The MT unit or the one from my ISP? Sounds like stupid but I have not come across this be4. Thanks for your time and help.

I just contacted my ISP and all they provided me is with the static IP address which I already know. No CSR info. was given. Any suggestion?